[Python-Dev] 2.7 Release? 2.7 == last of the 2.x line?

[Terry Reedy]

Guido van Rossum wrote:
> On Tue, Nov 3, 2009 at 9:37 AM, "Martin v. Löwis" <martin at v.loewis.de> wrote:
>> (and no, adding things like nonlocal to 2.7 doesn't making porting of
>> a real application or library any easier, since the existing application
>> or library simply doesn't use that keyword.
> 
> Agreed.
> 
>> In fact, no change to 2.x
>> can reasonably simplify porting - only changes to 3.x might - except
>> for changes to 2to3, which can simplify porting a lot. But 2to3 should
>> be run under 3.x, IMO.)
> 
> Disagreed. Better "-3" warnings could make porting easier. (Not just
> more warnings -- "better" might mean fewer false positives for
> warnings already issued.)

There is also Eric Smith's list to consider: PEP3118 new buffer 
protocol, short float repr, and maybe io.

> FWIW, it doesn't sound like killing 2.7 is a productive thing to do.
> However making 2.7 the end of the line (though with indefinite bugfix
> releases) might be. (Indefinite != infinite.)

I think you should decide and announce something like the following:
'''
Python 2.7 will be the final, stable release in the Python 2 line.
It will be released in mid-2010 with the first alpha scheduled for 
December 2009.
It will not intentionally break valid older 2.x code; this means no 
removals. (Valid == not exploiting a bug.)
Being the last of its line, there will be no deprecation warnings unless 
explicitly requested with the -3 flag to warn about incompatibilities 
with 3.x.
There will be lots of bug fixes since 2.6.
There will be only a few new features, with those aimed at easing 
eventual transition of libraries to 3.x.
The period of 2.7.z bugfix releases should be longer than for previous 
x.y releases (as long as there are volunteers to write and review 
patches and prepare distributions).

The developers urge people with 2.x code, especially library 
maintainers, to test it with preliminary alpha or beta releases so 2.7 
can be as good as possible.

The developers hope OS distributions can move to including 2.7 as soon 
as feasible, even if it means 'skipping' 2.6 as a default version.
'''
[My intention with the last is to promote 2.7 as the definitive version 
of 2.x, though there might be better wording.]

Terry Jan Reedy